SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '842b651f051ebf75708ca4b5a6531450044f6bc9c4833b899f6865d20e2e61d5' 
  AND token = 'WFI1mxzDFc+McQNG4RpmjkQicmQF2IneXD/MwVEUCzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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