SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd52916bfa7e16c942bc67ce905da1240103b2ee39b809acb9b333aea1f5f7fed' 
  AND token = 'WAfWC4EAXOTMzb9QHmhF/xTLYCObxWw7Vk92Fzyn0gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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