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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a1b5e0126b5faffbbc93bc84c025de3f7c7af758fe9fe94cacee20095a64c08' 
  AND token = 'uzTgDIAkAe5RcHqKnZy+p4H2a6drFxGXVtwnDkr/bcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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