SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53847b627a27b99621985deb64541810b0fd3a3dd6de0aa45833506c72f01e27' 
  AND token = 'aPYkvZyhwFCOfxEKJ7WV5BEemBl6tL3NwKWr+VZ5bCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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