SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c248279726ba71c7b1895a916b6b75a3fa0e711af8e5b374cc88798dcc6e61a8' 
  AND token = 'OFwzIplF0m3v4njxhktpde+UJvW4zLBiZMCz46Y/HRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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