SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a03d311d01ccaa6123e23291eb29934511ef53f8fe7c432c456896be85f7e3d1' 
  AND token = 'yzL0JBvLuV6YcU6m+9a7d2SOolaAe//y1LlvblCjnCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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