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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5de9d1c56b43b6cb2fd422fc4c2d89486bede1d4a65a10d0dce8edc98689af0' 
  AND token = 'SCtrdnaCKyAJ3GaPBY5uNrDpibhJeYvFPOx+DMtJq+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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