SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c43411068f17c0ab54f1edd8846762a09279162c97029ec1d16375830b561b67' 
  AND token = 'aU7jhPzAVLjM1iG+lxPQvHB7q0oSkbjiBIH5OnpuMQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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