SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72142de3d238028b25c6ca4877a19f60a0a242ea438f4c3879a013e8135bee25' 
  AND token = 'EKhJckQwVdTEeD5QIiKWGTvcfpxtH0ud4DkMGcXQm7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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