SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2277f495579921dea059ba08af074bdb8c79feada600421fc05abd43cb11b91e' 
  AND token = 'o5ixg2OcMr0j2fhF5D9dmhDx6txEcxDBcBHosHUVDMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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