SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2517612978d2e9719cbe35455fce79b23f7c683fc344067003d9b44181de94a6' 
  AND token = '4YG0+Vbshv3kNRsydlJNxOGcUXKd2+YSwAsHO75Y4Do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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