SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d34a28c573c4a04b9359c9e5b65a1e91b79bd8d2dcf6f563fdeafd657370fd9' 
  AND token = 'nqkwzhCpSAqrDrMQGPw9Kx9V1j1EgpuBVJolplbl9Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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