SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ed869b571f72a25971bb65f4025661567738998bcf63bb99acb40202bf797e' 
  AND token = 'b6JVgM34WgbvWumNCDYVWCGy24lTPDTlrdoLXQId0XU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}