SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '254f0911e4a1bbf7b9ebf0c6177d1fc42ffed58f0f3989a6a8ecac5879b67762' 
  AND token = 'c9bFHR7NtbWe6Dm5Kj3weYHmGfNZ71EEgsbCySgVENM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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