SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf9431fb8b242e858e3d7eea932c3a9608ed72f1bf295d2a388356c841f15b36' 
  AND token = 'USvsdIjtM+YbRZXdaMVm0Cvt5uVUKBRwM2Kq+li/6Dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}