SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2450eb97da917766e7ae93b4c16e8525f55cb7e861e687beff3717c745b243f6' 
  AND token = 'BTtamcFgh7YtM/0EOmqiOJmHT0NSqhT0zhNAXvR9Ylw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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