SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63256bc6ff34bc77ee1a11fbef85c4db6a9cbbd733a2489021493db2c4b613db' 
  AND token = 'mdLUUHwERYXEZ7I6JXPnxcw13cSDdIsaWUlehAY3Dco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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