SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2cf0fbef76806096c884a089615122cda3c87233331ace3627f5a5dce788cd0' 
  AND token = 'XtHBhvHG+ASvLRFYYw0+3APNhlnxDxY+hdoCjFmDAIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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