SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77929ab854a2926e4d6b9ec2395f68236c1f0adf421414b8aaf27ff99362742e' 
  AND token = 'LtbGLhgdJ7Z8pHiWczsHC/itb2hn0vj/0pXmAWZX6Tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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