SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e90a184a61ed233537dbc27a288dcc98e4df12fce983fa8e110af90bab4c32bd' 
  AND token = '1+r08GUI8Bs4cdkVrGwA2GY3XyKVuUAcPRKe71QY4Jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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