SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aea0f110352850b44df74d2bb818e50c3ffdbbb72549588829c56aeec891c6c4' 
  AND token = 'I71LcgM/TiObn31dDzM2Pgjhqqf45osAD1sUk1aSoo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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