SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15d31d7a1381395bdd3bd205d7c958b2a90cb217fb1b3566e0c7312a4d573424' 
  AND token = 'bpU3yU0l8TLHBgAJFqoKhGwMXNZ69snJuNB0MhV4+jY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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