SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0288a58f4c745feb55c9f2c0928d2404dcbdded67896ea8149006ccd801c85e2' 
  AND token = 's3lDOUGmGrZwBM18an7zn1icdVVmwViOjLXT4UAGn6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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