SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0751634a35b765b7cf19cecc13a5efa442afe3274b7f0454b5f4242658950a05' 
  AND token = 'XDvp1WzbZlXhLlOUx8eGS/mYlQg4pUg54MzqMS+sqCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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