SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc8ff420776c3e30c57d928424857d1d9f3f56bb817ebbd4c35f5b2cdb098eb' 
  AND token = 'kCmoKPLNbqQejcROKaIhUZAjG+PvXSEwDIU4GS63+hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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