SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '857ba7dca8434fcc12207ed01fa815ae9e54ceace05dfe3ce69e77c8ec4cb102' 
  AND token = 'pP8KBsIVFLFdCbQPC7vjNSRtNjIBLnMBqIdZXy9Tipo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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