SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a138300162f5949a21ae8579f14302b16b36bdeef18b0f8d462c064cf5152171' 
  AND token = 'jJsw0w/7X3bm27imJSB1RZCMqUv9yQwmPpCO0UMyRQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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