SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd17309409a1397f485a3b87a3a23d82048fbe75061c14ffaa38edd8c5d413a45' 
  AND token = 'K/rqojJk2ScsOb4CwYvi+6La7aFSrPYB9YgWd7L5ZCo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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