SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8387a8a4bad9d4850ac17cc56dfc7fd3ad393882ce748c568aa9eeb65b15ea84' 
  AND token = 'NYc/q+iFoDSmTnd4lOkFrgK/He5nAnTluDP97Xgy1+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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