SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6dcd33d9045ec080b207b214bd394d5919b5b070e240193413f729bcab62b79' 
  AND token = '1S3VtR9faMPYj2NFpFZrKcxj4rjyBFedi48GGwkCfKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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