SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5576df9353fc45d2c26f0c2b6315188dde344fa4d04013be0903adc4867535d8' 
  AND token = 'QPnC6o88wJSOohmQR8VLa0kDVi7/zTcLCYSLgvKAJfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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