SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c817e368c7d01d693330df9a8ad1f2f82978db95895fa9a05c0ce1ffe7fe388' 
  AND token = '4/UXqFnrMVPweX7C+Jmhg97EuNmGnxYI/pe69rQcKLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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