SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27655d6f86cecec7b8ceba05e280d381348aa85398c1216d0a715fc009c95187' 
  AND token = 'BygcF2lyMy8TjHoZ1wZCa4LMrex17ZxD1I+dMMbdpjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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