SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bede4359285ed8d3e6236a5fb691c14aaaefc6f1b0378620e1a2d55cb46f6f44' 
  AND token = 'C6i6IotqGcUGVx638bv9fVkS7CfndYlzWbhpI+oiiEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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