SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8da2a20d770fe03b169d2731c9b2ef1a2f13280eaf468dfa1930724d2c9c3f62' 
  AND token = '3SiWVWBwEGMW0Nj22bQOtEcimDIPBoiso0nthiTUySI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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