SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c5d76c42bba6180d0e56e6dca11feff331c782a9f623d4fc039f91c025df73c' 
  AND token = 'vHANmhvRDXO+YM8BOc+w0mPYmzt++EOkHqb4CLaE96M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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