SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '842d8800fad57214c65da3caeb4fd348a279be257dcc1fc3e78631d512003a7e' 
  AND token = 'AEyDovJhZEGCzB7E3ldx6rclMnuqpwkLVidZhjpJJaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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