SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387d4b225a7dddf408abce882664dfa1439c3d9ea415cf8f1924b0b82c32d807' 
  AND token = 'vjvpb7hMKm6P7SJWwoZW2GnCorowJHE2dJH9qZjih3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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