SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5feb5b566ac3c9172e7fdd7715d4499138044448a453f1a65f7070a44bdcc1b8' 
  AND token = 'tTJG/V42TCEWLXpHq8Xyds+oMBM73LdE5jRL5lLMymQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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