SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5ff9d4881f4c16f2311faa4b7676155a19d2fd83a9779453731f3994b7298e0' 
  AND token = '399BqgPWYzIFJ9qDLewAxLuYfSsQ8pX1AZMwS059FvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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