SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2363bfd843a5d9ab649d6d1a91473481a32a90449c7733be414387f99b4f1cf9' 
  AND token = 'kGCc7vtaxL4m2AHE5bRHWr016mauZKtm/gYBjPyqUPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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