SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8477974678b58a6ddf528bb09e2318a290ab0aa691ee913a3efc2295793c6770' 
  AND token = 'JZ9gDssQEEL2BpXCd6lqvU0BBuj6xxAyc1Ay14E5Qvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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