SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b36902795a484a5793f5bedda9b4e460f9faf59876062b018bd347e00abf7884' 
  AND token = 'xCIvhyoEIxCWwPwx0CQRoRj54YUrP442TIcCluh82Fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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