SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '553ed39a19ed39d88c7ff62abc4baaf5120907e8796b146b2c131cb3b08770f6' 
  AND token = 'U428+Vxq97M1mn1+fd3D9TOkldDpgmj/w4iI2vgTyZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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