SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4acda8aa26227c1c68b92bf2fc8e82b73a015cad54fa90d6fa7e40ccb14be39' 
  AND token = '7v3SznKMZ//UB4CjGp/8c3kVty1KGr20FqVlFb/dJ+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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