SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de412ef0a9b536515ba8af9c8605ccdeae419ff6d6db1e845f644baf85665c21' 
  AND token = 'OQuQkWgfXlOMx7eoJwfVWVgPhlNlwqHIEOmMXvphA3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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