SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b8d71d8590619c40039a8c124b996a4d4cb2d5ec2caf27c6031fa69e4959f96' 
  AND token = 'F9I8OOs/EfKBlxLIeeyFjyreUCR6vAAuoTf6b7pR5PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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