SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11d17a3d68c22657d6253ede907d19f1a4838a07bd3738cb14c511769569a1e7' 
  AND token = 'KoTXNRIzu6g8iEKb0uj5BE3WTYSWkCTrGI4JMSYN8aQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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