SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddf4f89430320de7144d75d5f4fa14fb3c490af448f6f18f55df19aaec42b04a' 
  AND token = '3imfK4XkdS5G/dL2HcPbRHXrKvkEUJQQY1JgOdFhiwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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