SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c23a7b7c4f580f478bd4211625c2e4c802d6ab1f7e48c17633f9f589035c77' 
  AND token = '9/Mhmkh0OR81r5lfj+BF0YZbGNGDnYcirNvtMHSVf+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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