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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c30cd47143918bca1a7629e242d4d9bfea092a7304c8de8f1e0a1cf8685a152' 
  AND token = 'u0Rm/8Et0+VJ8Cj0TMPmviKwSIzPUCxEZKuXO7eeMps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}