SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a189647676d489fde30fd498e29ca732ee5644e56127f41a9463f64a401481' 
  AND token = '24kFGivCH7iKv3IJoyyp8QUW6cmbphGP2U31sHnOlVM=' 
  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"
    }
  }
}