SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '559a7475a116d2c276a3851dd22d558d6ec792274d57e8832fd5aa5e4eac2c02' 
  AND token = '2KDdoczUU/7gdnhXeFltbCdvNZx9tlm8ZV9VeYDVMiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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