SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5ce2d5f4b4ecb0e32f80134dc75df995293cb2ad4cd3c7b6f6ff8099bfd6472' 
  AND token = 'taTzm3kKtzbpRaq7Ml54cvqnZMcg3okmlB5iht6MOEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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