SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c9877c38f68639ffab8b5291388a9d66865db3ca8b8b2d391414977eb744244' 
  AND token = '8AOAcXvN67lFI7RiTsUUmgv2vhNrH52HJBL7u00tCaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}