SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8fe22d2ddb18ff3fcbb58b0712b2ded934dc2f71d23f5d46274e85b5f0b3affc' 
  AND token = 'lUt6TNFZJmjM+Lcsn84IINngWKLIMh2QzoI6+nKx+WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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