SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6f19a8881491e039e3aede68d7d08ea7e9f90ff4e93f7b59e6ff43f80015c18' 
  AND token = 'jtLf9CzKc0TjHktVGnxYzC/xmWPBHVoIBlCp2YmGwgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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